08:40 AM PST on Tuesday, November 29, 2005

By VINCE PATTON, KGW Staff

The U.S. Department of Homeland Security has quietly ranked the 15 greatest threats to the United States. At the top of its list is an improvised nuclear bomb placed by terrorists in an American city.

However an investigation by KGW reveals major weaknesses in the very defense Homeland Security relies on most to prevent its worst case scenario.

Since the attacks of September 11, 2001, the Department of Homeland Security has spent more than $300 million on radiation portal monitors for every border crossing in the country. However nuclear physicists say those monitors would fail to detect the most common fuel for a crude nuclear bomb.

Radiation Portal Monitors, RPMs, stand as towering, yellow metal "doorways" on every lane of truck traffic crossing from Canada into Blaine, Washington. Smaller versions monitor every lane for passenger cars. RPMs search for invisibile radioactivity to keep out materials for a nuclear bomb. The RPMs have been in place in Blaine since 2004. Similar monitors are planned for installation at the Port of Portland in 2006.

KGW photo

Radiation Portal Monitors are yellow metal "doorways" on truck crossing lanes from Canada into the U.S.

"We don't think it's particularly likely that we'd find a finished device here," says Jay Brandt, the Assistant Port Director for U.S. Customs & Border Protection. "It's much more likely to find some of the raw materials."

The portals are so sensitive, says Homeland Security, that they will pick up the barium in the blood of a truck driver who had radiation medical treatment.

"These are very sensitive detectors," says Brandt.

According to analysis by several scientists however, the portals would fail to detect highly enriched uranium, the most likely fuel for a crude nuclear bomb.

"It's easy to beat those systems," says Tom Cochran is a nuclear physicist with the Natural Resources Defense Council, whose analyses are often considered credible by experts in the Department of Homeland Security.

Cochran says "These systems cannot reliably detect highly enriched uranium smuggled through even if it goes right through the portal."

Highly enriched uranium is the key. It's dense, deadly and relatively little is required to make a bomb. A chunk the size of one soda can weighs 15 pounds. Just 10 cans would be enough for a 10-kiloton bomb, nearly as strong as the one that the U.S. dropped on Hiroshima, Japan in 1945.

Unlike the highly radioactive explosion it would cause, highly enriched uranium gives off very little radiation, which makes it very hard to detect.

Laura Holgate, Vice President of the Nuclear Threat Initiative, says, "It only takes a small layer of lead to hide it in transit. So all these wonderful radiation detectors we have at our ports, they're not going to find it."

Experts say these radiation monitors work best in combination with x-ray detection. In Blaine, U.S. Customs & Border Protection doesn't have enough equipment to send every truck through both.

The x-ray scan only happens if a truck sounds the first radiation alarm or if a border officer chooses to send them through.

Brandt says, "Well, we can't run all of the trucks through there. We just don't have the capacity.

Plus, x-ray scans are quite slow. A trip through the RPM lasts a matter of seconds but x-ray scans require a delay of several minutes.

Some experts fear a bomb is already in the works. Osama BinLaden has issued a decree that getting a nuclear bomb is a religious duty.

Highly enriched uranium sits all over the former Soviet Union and in 40 countries. Not all of it is secure.

"The priority has to be preventing nuclear weapons," says N.R.D.C.'s Cochran. His organization has joined the Nuclear Threat Initiative headed by former Senator Sam Nunn, in urging the government to focus instead on securing the weapons-grade uranium where it sits now rather than wait to try to catch it at the border.

Holgate, N.T.I.'s Vice President, says, "The most efficient place to spend money is in preventing the original theft and in securing it where it sits." Holgate spent two years as as Special Assistant to Assistant Secretary of Defense and she led the Department of Energy's Office of Fissile Materials Disposition from August 1998 to January 2001, responsible for consolidating and disposing of excess weapons plutonium and highly enriched uranium in the US and Russia.

While homeland security has spent more than $300 million dollars to put radiation portals at all of our borders, the Bush administration has not added any funding for keeping the uranium secure in other countries.

"People are not taking this risk seriously enough at the most senior levels and that lack of seriousness trickles down," says Holgate. "We see the right words and then we see action that hasn't changed noticeably since before 9/11."

Until the government tackles the first line of defense, keeping the nuclear fuel secure where it is, the radiation portals, limited as they may be, remain the last line of defense.

Brandt adds, "Nothing's an absolute but it provides a significant margin of safety over what we had before these. Because we didn't have anything before these."